.form {
    height:400px;
    width:40%;
    background-color:#f5f5f5;
    position:absolute;
    left:30%;
    top:20%;
    border-radius: 5px;
    border:1px solid #e3e3e3;
    visibility: hidden;
    opacity:0;
    transition: opacity 0.3s;
    -webkit-transition:opacity 0.3s;
}